8n tractor pressure plate

K

kurt v

Well-known member
What would be the correct springs to change a 8n plate to a 40 ford pp, seems like it would be an easy fix.

thanks
kurt
 
Mr Bob, are the weights you mention are they the weights on the end of the three levers on the out side of the housing ?

thanks kurt
 
kurt v said:
Mr Bob, are the weights you mention are they the weights on the end of the three levers on the out side of the housing ?

thanks kurt
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Yes
 

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I think 53 up didn't have the weights but 52 down does, that was my question, 9n, 2n , 8n, tractor was same pp but with heavier springs than the cars. Not sure , just what i thought i read.
 
Tractor pp are cheap compared to the car pp, for the cost of 6 springs it would be a big savings.
 
Are the fingers of your pressure plate adjustable on the tips? If the tractor version had the heavier springs, that's what most guys want for car applications. What's the intended application of this pressure plate you plan to use?
 
I just like to try to work around things, not trying to be cheap but for the reason to see if it can be done. My understanding is the tractors had the heavier springs , makes sense but used the same pp as the cars just with heavy springs for the clamping force for the work they did, cars don't need that and the car pp was being made before the 9n tractor was built so ford used it.
 
Some guys build their flatheads pretty healthy, and want the light weight rotating mass of the 9"pp AND stronger springs to prevent slippage. I would think the non adjustable fingers would be a pain. I might have a set of stock 9" springs that I removed, just to put
in a set of springs from a 10 or 11" pp that are stiffer. If you have a set of the so called stiffer springs from tractor pp, might be worth a trade.
 
According to the Ford shop manual the 9 1/4" pressure plate has the strongest springs. 51-7563 11 1/4" plate spring load 115-120 lbs. at 1.562", 90A-7563 9 1/4" plate 145-153 lbs. at 1.562", 81B-7563 11 1/4" plate 130-140 lbs. at 1.562" and 9A-7563 10 1/4" plate 125-135 lbs. at 1.562"
 
I'm confused when you mention 9 1/4, 10 1/4, and 11 1/4" plate... Weren't they 9, 9.5, 10, and 11" clutches?
 
That's the way the service manual lists them. I think the disc was
9,10,11 and the pressure plate was 1/4" larger.
 
Interesting info Bob, thanks for that. Any engine shop should have a spring tester, Which I planed to do with my slipping 9" some day when it gets to the top of the list. Now with that data, we know what it should be, and I'm sure to buy stiffer springs would be cheap enough. Certainly, all should be the same...so back to the tester machine.
 
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